Although most children with HIV will develop growth and nutritional abnormalities, the longitudinal effects of HIV on body composition and nutritional requirements are not known. Currently, nutritional therapy is often empiric and not consistent. The aims of this proposal are to detect body composition changes in HIV-infected children, to develop an algorithm to predict impending malnutrition, to determine both resting and total energy needs at different stages of infection, and to develop nutritional intervention modalities that are appropriate for the clinical stage of disease. We expect that the combination of early detection of body composition changes, determination of metabolic requirements, and successful nutritional rehabilitation will significantly improve resistance to infection, morbidity, quality of life, and possibly mortality of HIV-infected children. Our first goal is to study HIV- infected children longitudinally in early life as well as children who are currently followed and are symptomatic. The comparison group will be those children born to HIV-infected women, but who sero-revert. Children will periodically undergo nutritional evaluations with dietary intakes, traditional anthropometry, bioelectrical impedance, total body water, quality of life assessments, and selected biochemical studies. A subset of children will undergo cytokine analysis, indirect calorimetry, and studies with doubly labeled water. We will then be able to correlate in body composition with peripheral cytokine production, metabolic needs, and quality of life estimates. The second goal of this proposal is to determine effective nutritional interventions that will promote growth. Children will be enrolled in the intervention studies when they meet criteria for mild, moderate and severe nutritional deficits. The first intervention will randomize children with mild to moderate nutritional deficits to either a high energy diet alone or to a high energy diet plus omega-3-fatty acid supplement. The second intervention for severe nutritional deficits will be a longitudinal assessment of enteral feeding tube supplementation. Anthropometric parameters, bioelectric impedance, total body water, nutrient intake, quality of life assessment and frequency of hospitalizations with nutritional interventions will be of interest.